[regexp] Add slow exec stub to reduce code size

src/builtins/builtins-regexp.cc

Index: src/builtins/builtins-regexp.cc
diff --git a/src/builtins/builtins-regexp.cc b/src/builtins/builtins-regexp.cc
index 969cb19751d7ade0fa968fca2fb10a4704bd2f04..c477ad33c27419068e46434b7391a890bc67913d 100644
--- a/src/builtins/builtins-regexp.cc
+++ b/src/builtins/builtins-regexp.cc
@@ -455,10 +455,12 @@ Node* RegExpBuiltinsAssembler::IrregexpExec(Node* const context,
     Branch(IsTheHole(pending_exception), &stack_overflow, &rethrow);
 
     Bind(&stack_overflow);
-    TailCallRuntime(Runtime::kThrowStackOverflow, context);
+    CallRuntime(Runtime::kThrowStackOverflow, context);
+    Unreachable();
 
     Bind(&rethrow);
-    TailCallRuntime(Runtime::kRegExpExecReThrow, context);
+    CallRuntime(Runtime::kRegExpExecReThrow, context);
+    Unreachable();
   }
 
   Bind(&runtime);
@@ -736,6 +738,17 @@ void RegExpBuiltinsAssembler::BranchIfFastRegExpResult(Node* context, Node* map,
          if_ismodified);
 }
 
+// Slow path stub for RegExpPrototypeExec to decrease code size.
+TF_BUILTIN(RegExpPrototypeExecSlow, RegExpBuiltinsAssembler) {
+  typedef GenericTagged2Descriptor Descriptor;
+
+  Node* const regexp = Parameter(Descriptor::kFirst);
+  Node* const string = Parameter(Descriptor::kSecond);
+  Node* const context = Parameter(Descriptor::kContext);
+
+  Return(RegExpPrototypeExecBody(context, regexp, string, false));
+}
+
 // ES#sec-regexp.prototype.exec
 // RegExp.prototype.exec ( string )
 TF_BUILTIN(RegExpPrototypeExec, RegExpBuiltinsAssembler) {
@@ -764,8 +777,11 @@ TF_BUILTIN(RegExpPrototypeExec, RegExpBuiltinsAssembler) {
 
   Bind(&if_isslowpath);
   {
-    Node* const result =
-        RegExpPrototypeExecBody(context, receiver, string, false);
+    Handle<Code> code = isolate()->builtins()->RegExpPrototypeExecSlow();
+    const auto desc = GenericTagged2Descriptor(isolate());
+    Callable callable(code, desc);
+
+    Node* const result = CallStub(callable, context, receiver, string);
     Return(result);
   }
 }
@@ -1482,11 +1498,7 @@ Node* RegExpBuiltinsAssembler::RegExpExec(Node* context, Node* regexp,
   BranchIfFastRegExp(context, map, &if_isfastpath, &if_isslowpath);

[Igor Sheludko, 2017/03/13 16:30:32]

I guess it's better to skip this check and jump directly to slow path.

[jgruber, 2017/03/17 09:51:22]

Done.

 
   Bind(&if_isfastpath);
-  {
-    Node* const result = RegExpPrototypeExecBody(context, regexp, string, true);
-    var_result.Bind(result);
-    Goto(&out);
-  }
+  Unreachable();
 
   Bind(&if_isslowpath);
   {
@@ -1525,8 +1537,11 @@ Node* RegExpBuiltinsAssembler::RegExpExec(Node* context, Node* regexp,
       ThrowIfNotInstanceType(context, regexp, JS_REGEXP_TYPE,
                              "RegExp.prototype.exec");
 
-      Node* const result =
-          RegExpPrototypeExecBody(context, regexp, string, false);
+      Handle<Code> code = isolate->builtins()->RegExpPrototypeExecSlow();
+      const auto desc = GenericTagged2Descriptor(isolate);
+      Callable callable(code, desc);
+
+      Node* const result = CallStub(callable, context, regexp, string);
       var_result.Bind(result);
       Goto(&out);
     }